JavaScript Top 10 Methods For Arrays

Here I will be sharing my top 10 methods for arrays in js.

1. push( element )

2. pop( )

3. indexOf( element, initial index )

4. at( index )

5. forEach( callbackFunction )

6. includes ( element )

7. toString ( )

8. flat( nestingLimits )

9. concat( …element, …element, etc.. )

10. reverse()

push ( element )

Push method adds element in the end of the array.

const nums = [1, 3, 5];
console.log(nums);          // output : [1, 3, 5]

nums.push(7);
console.log(nums);          // output : [1, 3, 5, 7]

pop ()

Pop removes the element from the end of the array and also returns that removed element.

const nums = [1, 2, 3, 4, 5];
console.log(nums);              // output : [1, 2, 3, 4, 5]

let removedValue = nums.pop();
console.log(removedValue);      // output : 5
console.log(nums);              // output : [1, 2, 3, 4]

indexOf ( element, initial index )

It searches the element in the array and returns the index of that element. Using this method we can also set the initial index from that the element to be searched.

// indexOf(element, initial index)

const nums = [1, 2, 3, 4, 5];
console.log(nums);                  // output : [1, 2, 3, 4, 5]

// Searching element without initial index
console.log(nums.indexOf(2));       // output : 1

// Searching element with initial index
console.log(nums.indexOf(5, 2));    // output : 4
console.log(nums.indexOf(1, 3));    // output : -1

at ( index )

It returns the element present on the index if found. This method accepts both positive indexing (0 to length - 1 ) and negative indexing (-length to -1 ).

const nums = [1, 2, 3, 4, 5];
console.log(nums);                  // output : [1, 2, 3, 4, 5]

// Positive indexing => 0, .....(Array.length - 1)
console.log(nums.at(2));            // output : 3
console.log(nums.at(6));            // output : undefined

// Negative indexing =>  -(Array.length), ........ -1,
console.log(nums.at(-5));       // output : 1
console.log(nums.at(-6));       // output : undefined

forEach( callbackfun(value, index, Array) )

With this method, we can iterate through the arrays and access each element seprately.

const nums = [1, 2, 3, 4, 5];
console.log(nums);                  // output : [1, 2, 3, 4, 5]

/* In this iteration we are only accessing values 
so we don't have to write index and Array. */
nums.forEach((element) => {
    console.log(element);
})

/*  output :
    1
    2
    3
    4
    5
*/

includes ( element , initial index )

It searches the element in the array and returns true if found otherwise false. It doesn't return the index like indexOf() method.

const nums = [1, 2, 3, 4, 5];
console.log(nums);                  // output : [1, 2, 3, 4, 5]

// Searching element without initial index
console.log(nums.includes(2));       // output : true

// Searching element with initial index 
console.log(nums.includes(5, 2));    // output : true
console.log(nums.includes(1, 3));    /*// output : false => after index 3
                                         not a single 1 is present. */

toString ( )

This method creates a new string from the Array and return the string. It doesn't manipulates the original Array.

const nums = [1, 2, 3, 4, 5];
console.log(nums);                  // output : [1, 2, 3, 4, 5]

//  take temp to store the converted string
const temp = nums.toString();
console.log(temp);                  // output : 1,2,3,4,5
console.log(typeof temp);           // output : string

// Checking original array
console.log(nums);                  // output : [1, 2, 3, 4, 5]

flat ( depth )

This method removes the depth in the array and creates a new array. It doesn't manipulate the original array.

const nums = [1, [2, 3, [4, 5]]];   // Highest depth : 2
console.log(nums);                  // output : [ 1, [ 2, 3, [ 4, 5 ] ] ]

console.log(nums.flat(1));          // output : [ 1, 2, 3, [ 4, 5 ] ]
console.log(nums.flat(2));          // output : [ 1, 2, 3, 4, 5 ]

// Checking original Array
console.log(nums);                  // output : [ 1, [ 2, 3, [ 4, 5 ] ] ]

concat ( …value1, …value2, …etc )

This method joins all arrays and returns a new array. It doesn't manipulate the original array.

const nums1 = [1, 2, 3];
const nums2 = [4, 5, 6];
const nums3 = [7, 8, 9];
console.log(nums1, nums2, nums3);        //output : [ 1, 2, 3 ] [ 4, 5, 6 ] [ 7, 8, 9 ]

// Joining all arrays in single array
const temp = nums1.concat(...nums2, ...nums3);
console.log(temp);                       // output : [1, 2, 3, 4, 5, 6, 7, 8, 9]

reverse ( )

This method changes the order of the order of the element in the array and also changes the original array.

const nums = [1, 2, 3, 4, 5, 6, 7, 8, 9];
console.log(nums);            //outptut : [1, 2, 3, 4, 5, 6, 7, 8, 9]

nums.reverse();
console.log(nums);            // output : [9, 8, 7, 6, 5, 4, 3, 2, 1]

So this was my top 10 methods for array in JavaScript. I know that I haven’t added map, filter and reduce for my personal reasons.